1. Field of the Invention
This invention relates to a culture observation apparatus that is used for observing cultured cells while culturing the cells.
2. Description of the Related Art
In the field of biological research, various experiments have been conducted with the use of cultured cells for the study of dynamic changes in living organisms. The cultured cells are placed in a carbon dioxide incubator that is kept at an inner temperature of 37° C., a carbon dioxide gas concentration of 5%, and a humidity of 100%, together with a liquid referred to as a culture medium made from bovine-serum or the like, so that the activities of the cultured cells are maintained. Moreover, observation apparatuses, which allow observation while the activities of the cultured cells are maintained with the use of a microscope equipped with functions of the carbon dioxide incubator, have been commercially available.
In such an observation apparatus, the tip portion of an objective lens of a microscope is located inside the carbon dioxide incubator, and exposed to a highly humid environment. For this reason, moisture enters the inside of the objective lens, and tends to cause dew condensation on the surface of a lens inside the objective lens. The dew condensation inside the objective lens causes degradation in observed images.